We have been experiencing regular kitchen sink blockages and now the blockage is total. I've tried everything to unblock it from spring coils to guaranteed sink unblockers. I need to take out the new plastic connection to the old cast iron and re-make the cast iron connection into the soil stack. Do the old cat iron fittings unscrew, or are they pushed in and sealed with cement? The soil stack looks like 4" and the initial bend looks like 3" and the elbow in cast is 11/4" approx. This has been connected to 40mm plastic with some more bends.

martyn walker, April 2008

There's no facility that I can find to thank John for his wisdom. His answer was spot on and in the end I used a circular cutter to remove the offending double bend and joint, finding a suitable plastic connector that fitted into the remaining cast iron pipe, then bonding it in with a two part filler. Cheers, Martyn

MArtyn, May 2008

Cast iron fittings are pushed in, and maybe sealed with cement or even lead.....Screwfix do flexi waste couplings made by 'Floplast' which could save your bacon here! Good luck with this nightmare....I hate cast - gimme plastic everytime.

John, April 2008